package com.hmdp.service.impl;

import cn.hutool.Hutool;
import cn.hutool.core.bean.BeanUtil;
import cn.hutool.core.util.BooleanUtil;
import cn.hutool.core.util.StrUtil;
import cn.hutool.json.JSONObject;
import cn.hutool.json.JSONUtil;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.hmdp.dto.Result;
import com.hmdp.entity.RedisData;
import com.hmdp.entity.Shop;
import com.hmdp.mapper.ShopMapper;
import com.hmdp.service.IShopService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.utils.CacheClient;
import com.hmdp.utils.RedisConstants;
import com.hmdp.utils.SystemConstants;
import org.springframework.beans.BeanUtils;
import org.springframework.data.geo.Distance;
import org.springframework.data.geo.GeoResult;
import org.springframework.data.geo.GeoResults;
import org.springframework.data.redis.connection.RedisGeoCommands;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.domain.geo.GeoReference;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import javax.annotation.Resource;

import java.time.LocalDateTime;
import java.util.*;
import java.util.concurrent.Executor;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.TimeUnit;

import static com.hmdp.utils.RedisConstants.*;
import static com.hmdp.utils.SystemConstants.DEFAULT_PAGE_SIZE;

/**
 * <p>
 * 服务实现类
 * </p>
 *
 * @author 虎哥
 * @since 2021-12-22
 */
@Service
public class ShopServiceImpl extends ServiceImpl<ShopMapper, Shop> implements IShopService {
    @Resource
    private StringRedisTemplate stringRedisTemplate;

    @Resource
    private CacheClient cacheClient;

    @Override
    public Result queryById(Long id) {
        //解决缓存穿透
        //Shop shop = cacheClient.queryWithPassThrough(CACHE_SHOP_KEY, id, Shop.class, this::getById, 20L, TimeUnit.SECONDS);

        //互斥锁解决缓存击穿
        //Shop shop = queryWithMutex(id);

        //逻辑过期解决缓存击穿
        Shop shop = cacheClient.queryWithLogicalExpire(CACHE_SHOP_KEY, id, Shop.class, this::getById, 20L, TimeUnit.SECONDS);

        if (shop == null) {
            return Result.fail("店铺不存在");
        }
        //7.返回
        return Result.ok(shop);
    }

    /*private static final ExecutorService CACHE_REBUILD_EXECUTOR = Executors.newFixedThreadPool(10);

    public Shop queryWithLogicalExpire(Long id) {
        String key = CACHE_SHOP_KEY + id;
        //1.从Redis查询缓存
        String jsonShop = stringRedisTemplate.opsForValue().get(key);
        //2.判断是否命中
        if (StrUtil.isBlank(jsonShop)) {
            //3.未命中,直接返回
            return null;
        }
        //4.命中, 把json反序列化为对象
        RedisData redisData = JSONUtil.toBean(jsonShop, RedisData.class);
        JSONObject data = (JSONObject) redisData.getData();
        Shop shop = JSONUtil.toBean(data, Shop.class);
        //5.判断是否过期
        LocalDateTime expireTime = redisData.getExpireTime();
        if (expireTime.isAfter(LocalDateTime.now())) {
            //5.1未过期,直接返回店铺信息
            return shop;
        }
        //5.2过期,需要缓存重建
        //6.缓存重建
        //6.1获取互斥锁
        String lockKey = LOCK_SHOP_KEY + id;
        boolean isLock = tryLock(lockKey);
        //6.2判断获取互斥锁是否成功
        if (isLock) {
            //6.3 再次判断缓存是否过期
            jsonShop = stringRedisTemplate.opsForValue().get(key);
            if (StrUtil.isNotBlank(jsonShop)) {
                redisData = JSONUtil.toBean(jsonShop, RedisData.class);
                expireTime = redisData.getExpireTime();
                data = (JSONObject) redisData.getData();
                if (expireTime.isAfter(LocalDateTime.now())) {
                    //缓存已被其他线程更新,直接返回
                    return JSONUtil.toBean(data, Shop.class);
                }
            }
            //6.4成功,开启独立线程,实现缓存重建
            CACHE_REBUILD_EXECUTOR.submit(() -> {
                try {
                    //缓存重建
                    this.saveShop2Redis(id, 20L);
                } catch (Exception e) {
                    throw new RuntimeException(e);
                } finally {
                    //释放锁
                    unLock(lockKey);
                }
            });
        }
        //6.5失败,返回过期的商铺信息
        return shop;
    }*/

    /*private boolean tryLock(String key) {
        Boolean flag = stringRedisTemplate.opsForValue().setIfAbsent(key, "1", 10, TimeUnit.SECONDS);
        return BooleanUtil.isTrue(flag);
    }

    private void unLock(String key) {
        stringRedisTemplate.delete(key);
    }*/

//    /**
//     * 互斥锁解决缓存击穿
//     *
//     * @param id
//     * @return
//     */
    /*public Shop queryWithMutex(Long id) {
        String key = CACHE_SHOP_KEY + id;
        //1.从Redis查询缓存
        String jsonShop = stringRedisTemplate.opsForValue().get(key);
        //2.判断是否存在
        if (StrUtil.isNotBlank(jsonShop)) {
            //3.存在,直接返回
            return JSONUtil.toBean(jsonShop, Shop.class);
        }
        // 判断命中的是否是空值
        if (jsonShop != null) {
            // 返回一个错误信息
            return null;
        }
        //4.缓存重建
        //4.1获取互斥锁
        String lockKey = LOCK_SHOP_KEY + id;
        Shop shop = null;
        try {
            boolean isLock = tryLock(lockKey);
            //4.2判断是否获取成功
            if (!isLock) {
                //4.3获取失败,休眠
                Thread.sleep(50);
                return queryWithMutex(id);
            }
            //再检查一次缓存是否存在
            jsonShop = stringRedisTemplate.opsForValue().get(key);
            if (StrUtil.isNotBlank(jsonShop)) {
                //存在,直接返回
                return JSONUtil.toBean(jsonShop, Shop.class);
            }
            //4.4获取成功,根据ID查询数据库
            shop = getById(id);
            //5.数据库里不存在,返回错误
            if (shop == null) {
                stringRedisTemplate.opsForValue().set(key, "", CACHE_NULL_TTL, TimeUnit.MINUTES);
                return null;
            }
            //6.数据库里存在,写入Redis
            stringRedisTemplate.opsForValue().set(key, JSONUtil.toJsonStr(shop), CACHE_SHOP_TTL, TimeUnit.MINUTES);
        } catch (InterruptedException e) {
            throw new RuntimeException(e);
        } finally {
            //释放锁资源
            unLock(lockKey);
        }

        //7.返回
        return shop;
    }*/

//    /**
//     * 解决缓存穿透
//     *
//     * @param id
//     * @return
//     */
    /*public Shop queryWithPassThrough(Long id) {
        String key = CACHE_SHOP_KEY + id;
        //1.从Redis查询缓存
        String jsonShop = stringRedisTemplate.opsForValue().get(key);
        //2.判断是否存在
        if (StrUtil.isNotBlank(jsonShop)) {
            //3.存在,直接返回
            return JSONUtil.toBean(jsonShop, Shop.class);
        }
        // 判断命中的是否是空值
        if (jsonShop != null) {
            // 返回一个错误信息
            return null;
        }
        //4.不存在,根据id去数据库查询
        Shop shop = getById(id);
        //5.数据库里不存在,返回错误
        if (shop == null) {
            stringRedisTemplate.opsForValue().set(key, "", CACHE_NULL_TTL, TimeUnit.MINUTES);
            return null;
        }
        //6.数据库里存在,写入Redis

        stringRedisTemplate.opsForValue().set(key, JSONUtil.toJsonStr(shop), CACHE_SHOP_TTL, TimeUnit.MINUTES);
        //7.返回
        return shop;
    }
*/
    /*public void saveShop2Redis(Long id, Long expireSeconds) throws InterruptedException {
        //1.查询店铺数据
        Shop shop = getById(id);
        // 模拟缓存重建时间
        Thread.sleep(200);
        //2.封装逻辑过期时间
        RedisData redisData = new RedisData();
        redisData.setData(shop);
        redisData.setExpireTime(LocalDateTime.now().plusSeconds(expireSeconds));
        //3.写入redis
        stringRedisTemplate.opsForValue().set(CACHE_SHOP_KEY + id, JSONUtil.toJsonStr(redisData));
    }*/


    @Override
    @Transactional
    public Result update(Shop shop) {
        Long id = shop.getId();
        if (id == null) {
            return Result.fail("店铺ID不能为空");
        }
        //1.更新数据库
        updateById(shop);
        //2.删除缓存
        stringRedisTemplate.delete(CACHE_SHOP_KEY + id);
        return Result.ok();
    }

    @Override
    public Result queryShopByType(Integer typeId, Integer current, Double x, Double y) {
        //1.判断是否需要根据坐标查询
        if (x == null || y == null) {
            //1.1.不需要坐标查询, 按数据库查询
            Page<Shop> page = query()
                    .eq("type_id", typeId)
                    .page(new Page<>(current, DEFAULT_PAGE_SIZE));
            //1.2.返回数据
            return Result.ok(page.getRecords());
        }
        //2.计算分页参数
        int from = (current - 1) * DEFAULT_PAGE_SIZE;
        int end = current * DEFAULT_PAGE_SIZE;
        //3.查询Redis, 按照距离排序, 分页. 结果: shopId, distance
        String key = SHOP_GEO_KEY + typeId;
        GeoResults<RedisGeoCommands.GeoLocation<String>> results = stringRedisTemplate.opsForGeo().search(
                key,
                GeoReference.fromCoordinate(x, y),
                new Distance(5000),
                RedisGeoCommands.GeoRadiusCommandArgs.newGeoRadiusArgs().includeDistance().limit(end)

        );
        //4.解析出id
        if (results == null) {
            return Result.ok(Collections.emptyList());
        }
        List<GeoResult<RedisGeoCommands.GeoLocation<String>>> list = results.getContent();
        if (list.size() <= from) {
            return Result.ok(Collections.emptyList());
        }
        //4.1.截取 from ~ end的部分
        List<Long> ids = new ArrayList<>(list.size());
        Map<String, Distance> distanceMap = new HashMap<>(list.size());
        list.stream().skip(from).forEach(result -> {
            //4.2.获取店铺id
            String shopIdStr = result.getContent().getName();
            ids.add(Long.valueOf(shopIdStr));
            //4.3.获取距离
            Distance distance = result.getDistance();
            distanceMap.put(shopIdStr, distance);
        });
        //5.根据id查询shop
        String idStr = StrUtil.join(",", ids);
        List<Shop> shops = query().in("id", ids).last("ORDER BY FIELD (id," + idStr + ")").list();
        for (Shop shop : shops) {
            shop.setDistance(distanceMap.get(shop.getId().toString()).getValue());
        }
        //6.返回
        return Result.ok(shops);
    }
}
